Figure 7.4: Idealised schematics
of two advective feedback loops involving the thermohaline circulation (THC).
The signs attached to the arrows indicate the correlation between changes in the
quantity of the outgoing box with that of the ingoing box, e.g., warmer sea surface
temperatures (SST) lead to weaker THC. Resulting correlations of a loop are circled
and they indicate whether a process is self-reinforced (positive sign) or damped
(negative sign). A stabilising loop (left) is associated with changes in SST due
to changes in the advection of heat. This loop may give rise to oscillations.
The second loop (right) is due to the influence of advection of low latitude salty
waters into the areas of deep water formation. The resulting correlation is positive
and the loop may therefore cause instabilities.